ORA-16002: database already open for read-write access by another instance
Cause : The database has been opened for read-write access by another instance, and cannot be opened for read-only access by this instance.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
This instance must be opened for read-only access, or all other instances must first be shut down and re-opened for read-write access.
Well, the reason for above error is that i have taken the above script from a 11g database and running it on 10g database. 11g has bring some changes in password management. Below code is executed on 11g and user created successfully, which is expected result.